Modeling ALS in a dish: how organoids are transforming research

: Amyotrophic Lateral Sclerosis (ALS) is a rapidly progressive neurodegenerative disease characterized by the selective loss of upper and lower motor neurons, leading to muscle weakness, paralysis, and ultimately respiratory failure. The multifactorial etiology of ALS, encompassing genetic mutations, protein aggregation, oxidative stress, excitotoxicity, and dysregulated RNA metabolism, has hindered the development of effective therapies. Traditional animal and 2D cell models have provided important mechanistic insights but often fail to fully capture the human-specific and multicellular aspects of disease pathophysiology. Recent advances in induced pluripotent stem cell (iPSC)-derived organoids offer a promising human-based platform for ALS research, enabling the generation of disease-relevant neural and neuromuscular subtypes in three-dimensional architectures. These models recapitulate key pathological features, including protein mis-localization, neuromuscular junction defects, synaptic impairments, and glial contributions to motor neuron degeneration, while also serving as platforms for drug screening and mechanistic studies. Importantly, spinal and neuromuscular organoids bridge the gap between simplified in vitro systems and the complex human nervous system, providing a unique framework to study ALS pathogenesis. This review provides a comprehensive overview of the various differentiation protocols, experimental strategies and key results obtained to date, with a primary focus on validating and benchmarking organoid models, while also highlighting their limitations, emerging clinical applications, translational potential, and opportunities for personalized therapeutic discovery.